As represented by the laser printer, recently, the performance of an image forming apparatus of electrophotographic system for forming sharp images excellent in resolution has been dramatically improved. To enhance the final printing quality of the image forming apparatus, a further improvement in the fixing process is desirable.
A fixing apparatus used in the fixing process in such an image forming apparatus is described below.
FIG. 8 is a schematic view showing a structure of a conventional fixing apparatus, and FIG. 9 is a plan view of a support member of the conventional fixing apparatus. FIG. 10 is a schematic view showing hot air blown by hot air means in the conventional fixing apparatus in a bounced state on the surface of the support member, FIG. 11 is a schematic view showing hot air blown by hot air means in the conventional fixing apparatus in a creeping state under printing paper, and FIG. 12 is a schematic view showing hot air blown by hot air means in the conventional fixing apparatus in a state pressing the leading end of printing paper.
As shown in FIG. 8, in the conventional fixing apparatus 1, the hot air fixing system is employed. In this hot air fixing system, printing paper 3 is an example of a recording medium and toner 2 is an example of a recording material. When paper 3 (with an image transferred thereon), is conveyed, hot air from hot air means 4 is blown to the printing paper 3 supported by a support member 5. The toner 2 on the surface of the printing paper 3 is then heated and fused, and fixed on the printing paper 3.
The hot air means 4 includes heat energy applying means 7 for generating heat energy, and blowing means 9 for blowing air to the heat energy applying means 7.
In the hot air means 4, the hot air generating procedure is described by referring to FIG. 8. An air stream generated in the blowing means 9 is blown to the heat energy applying means 7. The air stream is heated by direct heat of the heat energy applying means 7 to be hot air. The hot air fuses the toner 2 on the surface of the printing paper 3 to fix on the printing paper 3.
In the fixing apparatus 1, of a conventional hot air fixing system as shown in FIG. 9, the portion of the support member 5 for mounting the printing paper 3 on is flat. As shown in FIG. 10, the hot air blown onto the printing paper 3 from the hot air means 4 is bounced on the flat surface of the support member 5 supporting the printing paper 3 from its back side. Accordingly, when the leading end 10 of the printing paper 3 rushes into the hot air means 4, as shown in FIG. 11, as part of the hot air bouncing on the surface of the support member 5 creeps into the back side of the printing paper 3 from the leading end 10 of the printing paper 3, the leading end 10 of the printing paper 3 is lifted and floats. As a result, as shown in FIG. 12, the floating leading end 10 of the printing paper 3 is pushed to the support member 5 side by the hot air blown this time from above. Accordingly, when the motion in FIG. 11 and FIG. 12 is repeated, fluttering of the leading end 10 of the printing paper 3 occurs. It hence leads to disturbance of toner image or uneven fixing near the leading end 10 of the printing paper 3.